Safety attachment for air brakes



March 28, E956 J F, ERGUSO 2,5@1,?15

SAFETY ATTACHMENT FOR AIR BRAKES Filed NOV. 19, 1946 lure/liar Jam 6 6 ff'afyzzsw Patented Mar. 28, 1950 TES "PATENT OFFEE This invention relates to new and useful improvements in air-brake attachments and more particularly to a safety attachment for air-brakesof railroad cars. I

The primary feature of this invention is to provide a device adapted to be used in connection with the air supply to the brakes, when the axle of the train wheels become overheated said device allows air to escape from the air supply to the brakes thereby reducing the air pressure in the supply line and applying the brakes.

Another feature of this invention is to provide a pipe connection between the air supply line and the brakes of a train, said pipe connection provided with fusible plugs, Which will easily melt when the wheel axles become overheated thereby allowing a loss of pressure in the air brake line and consequently setting of the brakes of the train.

A still further feature of this invention is to provide a device of this character that is eflicient and reliable in operation, relatively inexpensive to manufacture, and otherwise well adapted for the purposes for which the same is intended.

Other objects and advantages reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure l is a top plan view of one of the trucks of a railroad car showing the invention applied thereto;

Figure 2 is an enlarged sectional view taken on the line 22 of Figure 1;

Figure 3 is an enlarged sectional view taken on the line 3-3 of Figure 2; and,

Figure 4 is an enlarged fragmentary sectional view showing the fusible plug melted to open the air line.

Referring now to the drawing in detail, wherein for the purpose of illustration, I have disclosed a preferred embodiment of the invention, the numeral 5 represents a conventional form of railroad truck, which supports a train car (not shown) and disposed at each end of the truck 5 are conventional forms of journal boxings 6, in which the spindles '5 of the axles la are rotatably mounted in bearings 8.

The main air line 9 of the air-brake system is provided with a branch pipe IS, the outer ends H of said pipe being threaded at I 2 into a fitting H3.

The threaded end it of a metal tube it is threaded into the decreased inner end I8 oi the '2 Claims. (01. 246-169) 2 fitting l3, said inner threaded at l9 into the wall of the boxing 6.

The inner end of the tube It terminates adjacent the bearing 8 and isclosed by a plug 2| of lead or other fusible material held in position by a rivet or pin 22.

As the boxing 6 becomes overheated the lead;

sealing plug 2| in tube I6 melts thereby causing a loss of pressure in pipe line it] and setting the brakes of the train as shown in Figure 4.

Standard manually operated cutoff valves lfla are provided in pipe line In so that in the event; a hot box occurs, air pressure is reduced and the brakes are set, then the air pressure to the particular wheel where the hot box has occurred can be shut off by hand. Thus air pressure can again be built up throughout the entire system.

The rivet or pin 22 cooperates with the plug 2| in a novel manner. From tests that the inventor has made, he has found that the fusible metal will first melt on one side of the rivet, thereby reducing air pressure by an amount in the order of fifteen pounds, which will automatically apply the brakes and slow down the train. Approximately thirty seconds later, the fusible metal plug will be blown out and the air pressure will then be further reduced and the brakes will be fully set automatically. This rivet, therefore, provides that by use of automatic brakes, with which trains are now equipped, the train will not immediately go into full emergency stop, causing breakage of equipment and discomfort to passengers, but the rivet and fuse plug construction provides for a stop in two stages. This operation is illustrated in Figure 4 in the drawing, the plug 2| being illustrated as partially melted away on one side of the rivet 22, allowing a limited reduction of pressure in the air line. The figure also indicates one possible arrangement of the elements of this invention in relation to cooperating elements in a standard journal box, whereby unequal heating of the fuse plug by reason of contact of the tube l6 and a portion of the journal box bearing 8 will assure that one portion of the fuse plug will reach a melting temperature before another portion thereof. The rivet or pin 22 will, of course, serve to retain the remaining portion of the plug for a very short period of time after a first portion of the plug has melted. It is believed that the cooling effect of the air rushing from the tube while a portion of the plug still remains will tend to delay the melting of the remaining portion of the plug, so that a lapse of time in the order of about thirty seconds between the initial partial melting of the end l8 being externally plug and the complete removal thereof from the tube [6 is easily understood.

In view of the foregoing description taken in conjunction with the accompanying drawings it is believed that a clear understanding of the device will be quite apparent to those skilled in this art. A more detailed description is accordingly deemed unnecessary.

It is to be understood, however, that even though there is herein shown and described a preferred embodiment of the invention the same is susceptible to certain changes fully comprehended by the spirit of the invention as herein described and the scope of the appended. claims.

What is claimed as new is:

1. A fuse plug and air hose fitting for use with an air brake hose system and, a: journal box. in a railway car truck, comprising a fitting internal- 1y threaded at one end to receive an end of an air hose and having a neck externally threaded for insertion through a wall of said journalibox', a tubeexternally threaded at one end: for connection in the inner end of said neck, a pin extending diametrically through v the other end of said tube, and a mass: of material normally closing said other end and fusible at a predetermined temperature, said pin extending through said mass; said other end being in contact with a portion of the journal box bearing on one side of the tube only, thereby causingthat portion of the fusible mass adjacent said' portion of the bearing to fuse prior to the remaining portion ofthe fusible-mass.

2. A fuse plug and air hose fitting for use with an air brake hose system and a journal box in a railway car truck, comprising a fitting internally threaded at one end to receive an end of an air hose and having a neck externally threaded for insertion through a Wall of said journal box, a tube externally threaded at one end for connection in the inner end of said neck, the other end of said tube contacting the journal box bearing on one side of the tube, a pin extending diametrically through the other end of said tube, and a plug of material normally closing said other end and fusible at a predetermined temperature, saidpin. extending, through said plug temporarily retaining a portion of said plug in position after another'port'ion of the plug has been melted and thus allowing; for gradual decrease of pressure in an air brake system andgradual application of brakes when a journal box bearing becomes overheated.

JAMES-F. FERGUSON.

REFERENCES CITED The following references are of' record in thefi'le of this patent:

UNITED STATES. PATENTS Number Name Date 605,973 Pojarkow June 21, 1898 891 ,3 21 Hunt et'alr June. 23, 1908' 2,420,924 Whittaker May-20, I947 

